The Value of the Moon: How to Explore, Live, and Prosper in Space Using the Moon's Resources (2016)
Luna: Earth’s Companion in Space
Humans dreamed of touching the Moon for millennia. It was only within living memory that we actually left our planet and stepped upon the strange new world that lies on our celestial doorstep. Recently, an international flotilla of robotic probes mapped the properties and determined the processes of this lunar world. Amazingly, it found that the Moon contains the material and energy resources needed to establish a permanent, sustained human presence there. Water ice was found near the poles of the Moon—billions of tons of ice, trapped in its cold, dark regions. Areas close to these ice deposits are bathed in sunlight for most of the lunar year. Water and light are two resources that permit us to use the Moon to create new capabilities for spaceflight. Thus, the Moon is an object of great utility that offers us strategic and operational possibilities that other destinations in space do not.
Because the Moon is close, we can access it easily and continuously, unlike virtually any other deep space destination. The Moon’s nearness means that much of the initial work of producing water and preparing the surface for habitation can be done remotely with robots under the control of human operators on Earth. Unique among space destinations, the proximity of the Moon allows us to begin its development before sending people, making the lunar surface the most inexpensive space goal beyond low Earth orbit, where significant progress can be attained early. The low gravity of the Moon (one-sixth that of Earth) enables us to use its resources to provision ourselves with the air, water, and propellant needed for the interplanetary journeys that humanity will undertake in the future.
The Moon is a small, complex satellite with a protracted and fascinating history and evolution. The early history of the solar system, a distant age when planets collided, globes melted, and crusts were formed and bombarded by impacts of leftover debris, are recorded in the rocks and soil of the Moon. The Moon has a core, a mantle, and a crust. Giant impact craters and basins have excavated thousands of cubic kilometers of rock and then crushed, melted, and reassembled it into complex forms. Internal melting generated magmas, which were released onto the surface as massive outpourings of lava, flooding large regions of the lunar surface. Following this period of violent geological events, near quiet has presided over the last billion years. The fossilized world of the Moon intrigues us, challenging our understanding of how the universe works.
All of these attributes place the Moon in the high-value column when selecting future strategic directions for humans in space. We went there half a century ago largely because a human lunar landing was a dramatic space goal achievable within a reasonable amount of time. Now, this same proximity, coupled with the Moon’s intrinsic interest and resources, again makes it an attractive destination. As we consider this, it is important to know how we went before, what we learned and why the Moon is the logical next strategic goal for the American space program. I will relate the history of our efforts to return to the Moon and the multiple starts and stops of that effort. Like Sisyphus and his stone, each time we thought we were on the road back to the Moon, we seemingly rolled back to the beginning. But unlike Sisyphus, each failed attempt to restart lunar spaceflight resulted in the acquisition of new data and information that has shown us that the Moon is an even more useful and inviting destination than we had thought. It is a wandering and complex (but fascinating) story involving geopolitics, government spending, big science and technology, and national greatness.
The Moon as an Object of Wonder, Mystery, and Worship
As the largest object in our night sky, the Moon has always been an object of interest and awe. From our first gaze overhead, we have wondered about and studied it, charting its path across the heavens. Because the Moon’s shape and appearance changed with regularity, it suggested to early humans that there was order in the otherwise capricious and potentially dangerous unknown world around them. The Moon allowed the earliest life on Earth to measure the passage of time, predict the seasons, and plan ahead—survival skills important to all species. Early religious speculation involved the worship of nature. The Moon’s changing appearance over the course of a month, along with the passing of days and seasons, became the natural timepiece whose rhythms and cycles helped humans regulate their lives. The coincidence of the duration of the lunar cycle to human menses suggested a female presence in the heavens. In the pantheon of deities, Moon goddesses Artemis, Diana, and Selene oversaw the natural world.
Even after ancient nature worship had been largely abandoned in western culture, the Moon remained a timekeeper and an object of intrigue. Both Judaic and Muslim religious calendars are lunar-based, not solar-based. Because the lunar and solar cycles are not coincident, holidays such as Passover and Ramadan fall on different dates every year. Aside from its early, practical use as a timekeeper, the Moon also influenced culture. A full moon permitted considerable outdoor activity during preindustrial history, spawning tales and legends of werewolves and “lunacy”—the idea that a full moon (Luna) could induce unnatural and abnormal behavior and activity.1
We now know that Earth’s Moon has been, and will remain, intimately tied to human origins, history, and development. The Moon’s twenty-eight-day orbit around Earth acts as a stabilizing influence on the obliquity of Earth’s spin axis, causing it to be stable for extended geological periods. Without this stabilization, rapid and chaotic changes in the orientation of its spin axis would make Earth oscillate wildly between climatic extremes, as happened on Mars. The Moon’s rotation around Earth causes tides on its oceans and land, resulting in the development of periodically inundated coastal areas, sometimes below water and sometimes above it. Such terrain fluctuation is believed to have facilitated the development of land creatures, as marine species began to tolerate brief periods on dry land. Thus, because of its gravitational influence, the Moon was a major driving force in the evolution of life on Earth.
Anaxagoras (500–428 BCE) was among the first of the early Greeks philosophers to examine the Moon scientifically. He believed that the Moon did not shine from its own light, but merely reflected the light of the Sun. He also developed the first correct explanation of solar eclipses. Aristotle (384–322 BCE) believed that the Moon was a sphere, always showing the same hemisphere (the near side) to us. Aristarchus of Samos (310–230 BCE) calculated the distance between Earth and Moon at 60 Earth radii, an astonishingly good estimate (in its elliptical orbit, the Moon actually varies in distance between 57 to 64 Earth radii, or between 363,000 to 406,000 km).2
During the Middle Ages, leading up to the Renaissance, or roughly the fifth to the sixteenth centuries, the Moon was simply another object to astronomers, but it did play a key role in the development and evolution of modern physical science. Galileo (1564–1642), an Italian philosopher, physicist, and astronomer, not only observed the Moon with a primitive telescope but also conducted experiments on the laws of motion and was an early convert to the Copernican system of a heliocentric solar system. The recorded motions of the Moon and planets against a background of fixed stars by careful observers, such as the Danish court astronomer Tycho Brahe (1546–1601), led German scientist Johannes Kepler (1571–1630) to formulate his three laws of planetary motion. A key insight is that planets and moons orbit their primaries in elliptical paths, not circular ones, as Copernicus (1437–1543) had suggested. As the Renaissance gave way to the Age of Enlightenment, English physicist Isaac Newton (1643–1727) synthesized the observations of Tycho, and the laws of planetary motion by Kepler, into a unified theory of gravitation. Once again, the Moon played a critical role. As Newton observed an apple fall from a tree in his garden, he wondered if the force acting upon the apple was the same force that kept the Moon in its orbit around Earth. From this simple musing, he developed the laws of motion and universal gravitation, a mathematical system that explained the physical world in exquisite, clockwork detail.
Although the naked eye cannot resolve individual landforms on the Moon, patches of light and dark areas on its visible disc have been discussed since antiquity, leading to fanciful Rorschach-like interpretations, ranging from the famous “Man in the Moon” to rabbits, dogs, dragons, and a wide variety of other creatures or objects. The dark and light areas are caused by the Moon’s two principal terrains: the dark, smooth maria (Latin for “seas”) and the brighter, rougher terra (“land” or highlands). The association of the dark terrain with seas has a muddled history. Galileo is often credited with it, but he didn’t actually equate the dark areas with water; he only suggested that some “might” be so. Using the newly invented telescope, Galileo made drawings and wrote detailed descriptions of the complex landforms that make up the lunar surface.3 By observing the Moon during different phases and surface illuminations, he saw that its surface was not smooth, as some of the classical philosophers had surmised, but rough and jagged, consisting of towering mountains and most significantly, circular depressions in a wide variety of sizes. Even though the Moon’s near side had been thoroughly mapped and remapped by astronomers over the previous two hundred years, the use of the word “crater” (from the Greek word meaning cup or bowl) to describe these holes was not used until the late eighteenth century.
With the advent of increasingly more powerful telescopes, the landscape of the lunar near side became known in much greater detail (figure 1.1). Astronomers now moved past the Moon to the more interesting stars, nebulas, and galaxies beyond. Lunar studies were left to a few diehards, mostly amateur astronomers and rogue geologists. The vast bulk of work on the Moon in the nineteenth and early twentieth centuries dealt with descriptions and studies of its surface features and history—most pressingly, the problem of the origin of craters. There were two opposing camps regarding craters. One group held that volcanic explosions and eruptions formed craters, while the other group believed that craters were made by the impact of small bodies, such as asteroids and comets.4 This debate grew to near religious intensity, often with more heat than light being shed on the problem. The two proposed mechanisms had very different implications. The volcanic hypothesis suggested that the Moon was an active body, with internal heat and ongoing volcanism. The impact idea suggested instead that the Moon was cold and dead and might never have had any internal activity. To support their arguments, each side marshaled the best examples they could; few analogues from the study of Earth’s landforms were of any help. Although Earth has many volcanoes that have been studied for years, at the beginning of the twentieth century, no recognized terrestrial impact feature had as yet been described.
Figure 1.1. View of the waxing gibbous Moon generated from LRO WAC images. The dark, smooth plains (maria) are basaltic lava flows, mostly erupted before three billion years ago. The rough, heavily cratered highlands (terrae) are the remnants of the original lunar crust. Bright spots are fresh craters. (Credit 1.1)
In 1892, Chief Geologist of the US Geological Survey Grove Karl Gilbert, intrigued by the craters of the Moon, spent many nights studying the lunar surface through a telescope at Washington’s Naval Observatory. Gilbert had heard a lecture about meteorite fragments that had been collected near a feature known as Coon Butte in northern Arizona. Mineralogist Albert Foote described these iron meteorites and noted their proximity to Coon Butte, but did not go so far as to connect the two in origin. Gilbert decided to study Coon Butte as a possible impact crater. By carefully measuring the shape of the crater, he calculated the likely size of an impacting iron meteorite. He postulated that the remnants of such an object must currently exist beneath the floor of the crater and used a magnetic dip needle (designed to show variations in Earth’s magnetic field) to search for what he believed should be an enormous buried iron body below the surface. But after intensive mapping failed to reveal the buried meteorite, Gilbert reluctantly (and wrongly) concluded that the Coon Butte crater must be a volcanic steam vent.5 Today, Coon Butte is known as Meteor Crater and is considered the world’s first documented meteorite impact site. How did Gilbert get its origin so wrong, especially since he had specifically tested the impact idea?
Gilbert did not understand that an impact at extremely high velocities (greater than 10 km/second) produces such enormous energies that the projectile essentially vaporizes as a point-source release of energy; left behind is a big hole with no buried iron body beneath the crater floor. An impact event is very similar to the detonation of a nuclear bomb. In fact, the formation of Meteor Crater fifty thousand years earlier by the impact of an iron meteorite must have looked very much like a nuclear explosion, complete with blinding flash and subsequent mushroom cloud. Documentation that this crater formed by impact opened the floodgates to the recognition and cataloging of dozens of impact craters on Earth (a process that continues to this day). Study of these features taught scientists to recognize the physical and chemical effects of high velocity impact, knowledge that would become critical in future interpretations of samples from the Moon and for a startling new interpretation of Earth’s history as well.
The Moon as Destination: The Space Race
The idea that we might someday travel to the Moon was often the subject of imaginative fiction, but such a journey could not be seriously contemplated until Konstantin Tsiolkovsky, Hermann Oberth, and Robert Goddard had developed the basic principles of rocketry and spaceflight.6 The technology of rockets made great strides under the impetus of war, as Germany developed the world’s first intercontinental ballistic missile (ICBM), the A4 (or “V-2” as Hitler dubbed it). In the years following World War II, intensive work toward the development of larger and better ICBMs as weapons of war led to the advent of Earth-orbiting satellites (Soviet Sputnik in 1957 and American Explorer 1 in 1958) and ushered in the Space Age. War and space were tightly coupled from the beginning, since the first use envisioned for space revolved around its possible value as a battleground.
Given this background, it was inevitable that the Moon would emerge as a key object in the exploration of space. Indeed, trips to the Moon began shortly after the beginning of the Space Age with the flight of Luna 2 in 1959. This Soviet robotic probe hit the Moon after a three-day journey, making it the first man-made object to reach another extraterrestrial body. Because of the Moon’s prominence in the sky and its proximity to Earth, it quickly became the focus of the first race into space between the United States and the Soviet Union. In May 1961, responding to a growing sense of geopolitical competition, President John F. Kennedy declared a national goal of a human lunar landing by the end of the decade. It was widely assumed that the USSR had accepted America’s challenge and that the “Race to the Moon” was on. A series of activities in Earth orbit conducted by both nations soon followed, filling that decade with new space accomplishments, which included extravehicular activities (spacewalks), the rendezvous and docking of two orbital spacecraft, long-duration flights (up to two weeks), flights to extremely high altitudes in the hundreds of kilometers, and the mastery of complex orbital changes. All of these techniques would be needed for a human mission to the Moon.
Meanwhile, the United States launched a series of robotic spacecraft to examine and scout the Moon. These missions probed its surface, landed softly on it, examined the soil, took high-resolution images of its surface features, and prepared the way for future human missions. The Ranger (impactors), Surveyor (soft landers), and Lunar Orbiter series gave us a first-order understanding of lunar surface features, processes and history.7 Scientists and engineers learned that the surface was dusty, yet strong enough to support the weight of a lander and astronauts. Craters covered every square millimeter of its surface, ranging in size from microscopic to enormous basins spanning thousands of kilometers. The landscape of the far side of the Moon turned out to be very different from its near side, with a near-absence of the dark, smooth maria that cover much of the Earth-facing hemisphere. Many unusual landforms of non-impact origin were found in the maria, strongly suggesting its origin as volcanic lava flows. Assuming that most craters were formed by impact, their density and distribution suggested that the Moon was an ancient world. Its surface told a story of having being exposed to space for many millions to billions of years.
The results of the Apollo missions, along with 380 kg (842 pounds) of rock and soil samples returned to Earth, largely confirmed and extended these inferences.8 We found that the Moon is made up of some of the same rock-forming minerals widely found on Earth and that it formed almost 4.6 billion years ago, about the same time as Earth. The samples suggested that the early Moon had been nearly completely molten, covered by an “ocean” of liquid rock. After this magma solidified at 4.3 billion years, a barrage of asteroids and comets bombarded the Moon’s surface for the next 400 million years, mixing-up the crust and creating a rough, heavily cratered surface. A final cataclysmic series of large impacts about 3.9 billion years ago formed the youngest basins, including the large, prominent Imbrium basin on the near side. The low areas of impact basins slowly filled with volcanic lava over the next 800 million years. For most of the last couple of billion years, the Moon has been largely inactive, with only the occasional large-body impact punctuating the slow and steady “rain” of micrometeorites that continue to grinds the surface into a fine powder.
This brief sketch of the history and evolution of the Moon describes a more complex planetary body than had been imagined before the Space Age. The Moon’s scarred, ancient surface records not only its own history, but also that of impacts in the Earth-Moon system as well. Because the Moon has no atmosphere or global magnetic field, the dust grains of the lunar surface also record the particle output of the Sun for the last three billion years. With the Moon as a “witness plate” to events in this part of the universe, this geologic time capsule remains virtually untouched, waiting to be recovered and read. Although we found that the Moon is depleted in volatile elements compared to Earth, we have only explored the lunar surface with people at six sites, all relatively close to the equator and on the near side. One cannot help but wonder what possible surprises await us at the regions near the poles or on the far side.
Most people are familiar with the political and pop-culture effects the Space Race had on the world, but they are not as well versed on the profound scientific impact of the Apollo missions. For the first time, we had collected samples from another world, taken from sites of known location and geological context. We took what we learned from these physical samples and coupled it with the global data gained from the robotic precursors. Added to this knowledge was information attained from regional areas through remote sensing. Combining all of these data allowed us to reconstruct the story of the Moon with a high degree of fidelity. The most important discovery of the Apollo studies was recognition of the critical importance of the process of impact on the history and evolution of the solar system. From an elusive and questionable idea in the pre–Space Age era, the collision of solid objects became recognized as the dominant, fundamental process in planetary formation and evolution. Because we had learned to recognize the physical and chemical effects of hypervelocity impact through the study of the lunar samples, we soon recognized that large body impacts had occurred on Earth in the distant past. In particular, the extinction of the dinosaurs 65 million years ago was recognized to have happened simultaneously with the impact of an asteroid 10 kilometers in diameter. This observation, suggesting that impacts might cause mass extinctions of life, was soon extended to other extinction events evident in Earth’s fossil record.9 Some scientists now think that mass extinctions caused by impact may be one of the principal drivers of biological evolution. Thus, because we went to the Moon more than forty years ago, we now understand something very profound about the history of life on our home planet—an understanding that holds clues about our past and poses some sobering implications for our future.
The Moon as an Enabling Asset
For all of its impressive scientific and technical accomplishments, the Apollo program left many space advocates wanting. Because it was primarily driven by geopolitical conflict and designed to demonstrate our technical superiority, once Apollo had achieved its objective of “landing a man on the Moon and returning him safely to Earth,” as President Kennedy’s proclamation put it, there was no longer any reason to continue returning to the Moon or to go beyond into the solar system. Thus, the program held within itself the seeds of its own demise. The rates of expenditure acceptable during the Apollo program were simply not politically feasible for any follow-on space program.10 So the decision was made to make an attempt to lower the cost of spaceflight via a reusable space shuttle. While this effort did not succeed in lowering costs, the development of the shuttle led to some significant and unique capabilities. More importantly, it pointed the way toward an alternative architectural template for spaceflight, one in which small pieces, incrementally launched and then assembled in space and operated as a large system of systems, might multiply spaceflight capabilities carried out over a longer, more sustainable period of time. This template of operations reached its acme with the completion of the International Space Station (ISS).
As for missions to the Moon, there was only silence and isolation. Several attempts to fly an unmanned orbital mission to obtain additional global remote sensing data (which would permit better interpretation of the superb Apollo sample database) were unsuccessful. With the focus of the human program centered on the space shuttle and the subsequent building of a space station in low Earth orbit, little interest in additional lunar exploration was evident. Then, in the mid-1980s, a confluence of events occurred to focus attention once again on the Moon, an interest that continues to the present. First came the realization that after the building of the space station, an orbital transfer vehicle designed to reach high orbits, such as geosynchronous (~36,000 km or 22,000 miles high), was the obvious next step. A vehicle that can reach geosynchronous Earth orbit (GEO) can also reach the Moon. Thus, a series of studies focused on the possibility of lunar return, with an emphasis on longer, more permanent stays on the surface.
Figure 1.2. Orbital geometry of the Earth and Moon. The Earth-Moon system orbits the Sun within the plane of the ecliptic. The Moon’s orbital plane is inclined 5.1° from the ecliptic, and the Moon’s spin axis is tilted 6.7°. This results in a nearly perpendicular orientation of the Moon’s spin axis to the ecliptic (called obliquity) of 1.6°. This is in contrast the Earth’s obliquity of 23.4°.
The idea that we might want to remain on the Moon for longer periods of time inevitably led to the concept of obtaining some supplies locally, from the materials and energy found and available on the Moon. This concept, called in situ resource utilization (ISRU), is an essential skill for humans to master if we are to be significantly and permanently present in space and on other worlds.11 That realization led to a renewed interest in getting additional lunar data—most especially, data for the unique local environment found at the Moon’s polar regions. Because the spin axis of the Moon is nearly perpendicular to the ecliptic plane (figure 1.2), the Sun is always on the horizon at the poles. Some areas are in permanent darkness and hence, very cold. It was recognized that these “cold traps” might contain deposits of ice, along with other volatile substances deposited over geological time as water-bearing comets and asteroids collided with the Moon’s surface. Additionally, other areas near the poles might be bathed in permanent sunlight. This near-continuous energy source allows for the generation of electrical power during the long, two-week lunar night. At the time, we did not know the details of these hypothesized properties or even if they actually existed. However, over the past twenty years, a number of lunar robotic missions have revolutionized our knowledge of the Moon, and in particular the environment and deposits of the poles.
In 1994, the Department of Defense Clementine mission mapped the mineralogy and topography of the entire Moon from orbit. An improvised experiment on this flight used the spacecraft transmitter as a radio source to illuminate dark areas within craters near the poles. Analysis of radio echoes from the south pole suggested the presence of water ice in the crater Shackleton. This discovery was confirmed a few years later by the Lunar Prospector spacecraft, which found enhanced amounts of hydrogen at both poles. These discoveries stunned the lunar science community, since earlier results from the study of the Apollo samples had suggested that the Moon was bone-dry and always had been. Now, that concept—and our understanding of the Moon and its history—had to be reevaluated. Over the next few years, additional results from sample studies, remote sensing, and theoretical modeling culminated in the unequivocal detection of water vapor and ice during the impact of the LCROSS spacecraft, thus demonstrating beyond any doubt that significant deposits of water ice are present at both lunar poles. Conservative estimates of the amount of water ice run between several hundred million to more than a billion tons at each pole. Additionally, we have found that small areas near both poles are illuminated by the Sun for extended periods of time, some for more than nine-tenths of the year. All of this new lunar data has countries around the world planning ways to access the energy and resource bonanza at the poles of the Moon, available to those who arrive first.
Materials and energy are available on the Moon, two critical requirements for extended human presence. Water, in its decomposed form of hydrogen and oxygen, not only supports human life but is also the most powerful chemical rocket propellant known. Near-permanent solar energy is available proximate to the water-rich cold traps at the poles. The previously misleading image of the Moon as a barren, useless wilderness (as painted by Apollo results) has given way to a richer, more inviting, useful persona. The world now knows that the Moon is not simply another destination in space—but that it is an important enabling asset for spaceflight. Our current understanding of the Moon is vastly different from those early humans who first gazed up, grateful that they had the Moon to mark their calendars and chart the seasons. We now understand that the Moon is a world in its own right, an object located in our cosmic backyard whose resources we can access and use to travel throughout the solar system.
Our Future on Luna
Space engineer and visionary Kraftt Ehricke once said, “If God had intended man to be a space faring species, He would have given him a Moon.”12 This tongue-in-cheek statement is even more applicable today than when Ehricke first said it more than thirty years ago.
Why is the Moon a destination for humanity? Because it can be used to open up the frontier of space through the development of its material and energy resources. By harvesting the water ice and solar power available at the poles of the Moon, we create the ability for long-term human presence on the Moon and in near-Earth space. Water can fuel a permanent, reusable space transportation system that can access not only the lunar surface but also every other point between Earth and Moon. This zone, called cislunar space, is where 95 percent of our satellite assets reside. The ability to reach these places with people and machines will allow us to build space systems of extraordinary power and capability. Moreover, such a system can also take us to the planets beyond Earth and its Moon.13
We can use the Moon to learn how to live and work effectively and productively on another world. This goal requires us to learn how to build protective shelters, safe from the thermal and radiation extremes of deep space. To provision ourselves, we must learn how to extract our supplies from local resources, including life support consumables, and learn how to build infrastructure using local resources for construction materials. Once established on the lunar surface, we will use these new capabilities to explore our nearest neighbor in space as well as to build a “transcontinental railroad” in cislunar space and establish a permanent beachhead off Earth. On the Moon, we will learn how to explore a planet using the optimum combination of people and robots, each doing the tasks at which they uniquely excel. Finally, we will reveal and decipher the record of planetary and solar system evolution recorded in the rocks of the Moon. Some mysteries uncovered by the Apollo explorations revolutionized Earth science. Additional exploration will reveal even more startling secrets and continue to revolutionize our understanding of the world and universe around us.
Why is it important for the United States to make the Moon a high priority goal? Because the United States is not the only nation interested in it. This coin of international interest has two sides. On the positive side, our partners in current space endeavors, such as the International Space Station, have expressed great interest in human missions to the Moon. Some have begun the process of gathering detailed information from precursor robotic missions to enable future human missions to the Moon. How can we proclaim world leadership in space if we ignore a prominent destination that so many other nations are anxious to visit and exploit? Nations such as China have plans to explore and use the Moon with both robotic machines and with people. While their lunar intentions appear benign at present, they are developing capabilities now that could pose a threat to the security of this nation and other countries in the near future. Thus, there is a strategic dimension to American lunar presence. It is vital to the security and economic health of the community of nations that future societies in space develop according to pluralistic, democratic principles and that commerce is open to free markets, with respect for property rights and contract law. Although American presence in cislunar space does not guarantee such an outcome, our absence from this theater could well result in the reverse.
What makes the Moon both important and unique? It is close, interesting, and useful. The close proximity of the Moon to Earth means that we can always and easily access it, unlike the limited and infrequent launch windows to all other planetary targets. This nearness means that much of the early preparatory work at the Moon can be done by robots on the lunar surface, as directed from Earth. Thus, the first humans to return to the Moon can arrive at a fully functional, turnkey lunar outpost, assembled in advance by these teleoperated robots. Interest in the Moon derives from its role as a small planet of complex and interesting process and evolution. The Moon’s environment permits unique and specialized scientific and engineering experiments to be conducted—studies not possible anywhere else in the solar system. We will find the answers to questions surrounding our moon’s complexity and gain a fuller understanding of our home planet’s early evolution. The utility of the Moon lies in its material and energy resources, the access to which will allow us to acquire the knowhow and means for humanity to plant its first foothold on another world.